Question

A current of 8 A flows in a system of resistors as shown in figure. The potential difference VC –VA will be

• A. $5\Omega$
• B. $T_{1}$
• C. $T_{2}$
• D. $T_{1}$

Answer 1

Answer: (B)

$T_{1}$

Answer 2

: Let I be the current is flowing through arm DAB, then the current flowing through DCB will be $(8 - I)$

Then,

$I(5 + 6) = (8 - I)(4 + 2)$

11 I = 8×6 – 6 I

17 I = 48

$\therefore I = \frac{48}{17}A$

Voltage across $5\Omega$resistance

$V_{D} - V_{A} = I \times R = \frac{48}{17} \times 5 = \frac{240}{17}V$ …(i)

Voltage across $4\Omega$ resistance

$V_{D} - V_{C} = (8 - I) \times 4$

Subtracting (i) by (ii) we get.

$V_{D} - V_{A} - (V_{D} - V_{C}) = \frac{240}{17} - \frac{352}{17}$ ...(ii)

$\Rightarrow V_{A} - V_{C} = - 6.6V \Rightarrow V_{C} - V_{A} = 6.6V$